[PATCH v2 12/19] platform/x86/intel/tpmi: Turn TPMI_GET_SINGLE_ENTRY_SIZE() into a function

[Kuppuswamy Sathyanarayanan]

The macro computing a feature instance size has a few problems. Its
comment says the hardware reports the size in u32 units, but the
conversion to bytes is spelled as a shift by 2, so the comment and the
code have to be read together to see that they agree. Its body is a
single conditional expression wrapped in a statement expression that it
never needed. And it evaluates its argument twice.

Make it a plain static function, tpmi_get_single_entry_size(), which
fixes all three: the conversion becomes a multiply by sizeof(u32), there
is nothing left to wrap, and the argument is evaluated once and type
checked.

No functional change intended.

Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 drivers/platform/x86/intel/tpmi_common.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/platform/x86/intel/tpmi_common.c b/drivers/platform/x86/intel/tpmi_common.c
index 83362d4bb726..7f6cd0fb23d7 100644
--- a/drivers/platform/x86/intel/tpmi_common.c
+++ b/drivers/platform/x86/intel/tpmi_common.c
@@ -149,13 +149,18 @@ struct tpmi_feature_state {
 } __packed;
 
 /*
- * The size from hardware is in u32 units. This size is from a trusted hardware,
- * but better to verify for pre silicon platforms. Set size to 0, when invalid.
+ * Return the size of a single feature interface instance in bytes. The
+ * hardware reports it in u32 units. The value comes from trusted hardware,
+ * but is still worth verifying on pre silicon platforms, so return 0 when
+ * it is out of range.
  */
-#define TPMI_GET_SINGLE_ENTRY_SIZE(pfs)							\
-({											\
-	pfs->pfs_header.entry_size > SZ_1K ? 0 : pfs->pfs_header.entry_size << 2;	\
-})
+static u32 tpmi_get_single_entry_size(const struct intel_tpmi_pm_feature *pfs)
+{
+	if (pfs->pfs_header.entry_size > SZ_1K)
+		return 0;
+
+	return pfs->pfs_header.entry_size * sizeof(u32);
+}
 
 /* Used during auxbus device creation */
 static DEFINE_IDA(intel_vsec_tpmi_ida);
@@ -397,7 +402,7 @@ static int tpmi_mem_dump_show(struct seq_file *s, void *unused)
 	u64 off;
 	u8 *buffer;
 
-	size = TPMI_GET_SINGLE_ENTRY_SIZE(pfs);
+	size = tpmi_get_single_entry_size(pfs);
 	if (!size)
 		return -EIO;
 
@@ -445,7 +450,7 @@ static ssize_t mem_write(struct file *file, const char __user *userbuf, size_t l
 	void __iomem *mem;
 	int ret;
 
-	size = TPMI_GET_SINGLE_ENTRY_SIZE(pfs);
+	size = tpmi_get_single_entry_size(pfs);
 	if (!size)
 		return -EIO;
 
@@ -531,7 +536,7 @@ static void tpmi_set_control_base(struct intel_tpmi_info *tpmi_info,
 	void __iomem *mem;
 	u32 size;
 
-	size = TPMI_GET_SINGLE_ENTRY_SIZE(pfs);
+	size = tpmi_get_single_entry_size(pfs);
 	if (!size)
 		return;
 
-- 
2.43.0